Declines in insect biomass disrupt fundamental processes that recycle nutrients through ecosystems. Insects accelerate decomposition by breaking down leaf litter and animal remains, fragmenting organic matter and stimulating microbial activity. When insect abundance falls, those inputs are processed more slowly, altering the timing and availability of nitrogen, phosphorus, and carbon that plants and microbes depend on.
Evidence and primary drivers
Long-term monitoring by Hallmann Radboud University documented a dramatic reduction in flying insect biomass in protected areas of Germany, demonstrating that declines occur even where formal conservation exists. Research led by Seibold German Centre for Integrative Biodiversity Research iDiv Halle-Jena-Leipzig identified declines in forest arthropods linked to intensified management and landscape change. A global synthesis by Sánchez-Bayo University of Sydney and Wyckhuys KU Leuven highlighted widespread pressures such as habitat loss, intensive pesticide use, and climate change that underlie those trends. These studies establish the connection between anthropogenic drivers and reduced insect-mediated processes.
Consequences for nutrient dynamics
Reduced insect-driven fragmentation and consumption slows nutrient turnover, leading to greater accumulation of undecomposed litter in some systems and nutrient limitation in others. Slower decomposition can reduce short-term soil fertility, lowering plant growth and altering species composition. In soils where detritivorous insects regulate microbial communities, their loss can change microbial respiration and nitrogen mineralization rates, affecting greenhouse gas fluxes and long-term carbon storage. Declines in pollinators and herbivores also shift plant community structure, which feeds back to the quantity and quality of organic inputs returning to the soil.
Human communities and landscapes experience downstream effects. Agricultural systems that depend on rapid nutrient recycling and natural pest control may require greater fertilizer inputs where insect-mediated processes falter, with economic and environmental costs. In many territories, traditional agroecological practices are intimately tied to healthy insect assemblages; losses therefore carry cultural as well as ecological implications. Regionally, changes to nutrient cycling can interact with water quality, increasing nutrient runoff or altering sediment dynamics in watersheds.
Addressing these impacts requires protecting and restoring habitat connectivity, reducing reliance on broad-spectrum insecticides, and adopting land management that supports diverse insect functional groups. Monitoring programs that link insect biomass, decomposition rates, and soil nutrient measures will be essential to track recovery and guide policy that sustains both ecosystem function and human livelihoods.